Vacuole segregation in the Saccharomyces cerevisiae vac2-1 mutant: structural and biochemical quantification of the segregation defect and formation of new vacuoles

The conditional vacuolar segregation mutant vac2-1 [Shaw and Wickner (1991) EMBO J. 10, 1741-1748] shifted to non-permissive temperature (37 degrees C), forms large-budded cells without a vacuole in the bud, and daughter cells without an apparent vacuole. Some cells still contain normal segregation structures. Structural and biochemical quantification of the segregation defect showed that (i) about 10% of the full-grown buds did not contain a vacuole, (ii) about 15% of the small cells washed out of a population growing in an elutriation chamber at 37 degrees C, did not contain a visible vacuole, and (iii) 15% of the cells per generation lost carboxypeptidase Y activity after proteinase A depletion. Thus, 10-15% of the daughter cells did not inherit vacuolar structures or vacuolar proteolytic activity from the mother cell. To investigate the fate of vacuole-less daughters, these cells were isolated by optical trapping. The isolated cells formed colonies on agar plates that consisted of cells with normal vacuoles, both at 23 and 37 degrees C. Thus, the vacuole-less cells that failed to inherit proteolytic activities from the mother cell apparently give rise to progeny containing structurally normal vacuoles. Time-lapse experiments showed that vacuole-less daughter cells formed vacuolar vesicles that fused into a new vacuole within 30 min. Although new buds only emerged after a vacuole had formed in the mother cell, the temporary lack of a vacuole had little effect on growth rate. The results suggest that an alternative pathway for vacuole formation exists, and that yeast cells may require a vacuole of some minimal size to initiate a new round of budding.     

Optimizing Drying Conditions for Microwave-Vacuum (MIVAC®) Drying of Russet Potatoes (Solanum tuberosum)

MIVAC® combines microwave heating with vacuum drying. Microwave power is modulated based upon product temperature and can limit overheating compared to other microwave-vacuum methods. Blanched potatoes were dried at 50, 60, and 70°C for 0 to 150 min. Potatoes dried at 70°C had a lower moisture content in less time compared to potatoes dried at 50 and 60°C, but the color of the dehydrated potatoes was affected due to overheating. Drying at 60°C for 150 min resulted in dried potatoes with acceptable color. Drying at 50°C resulted in dehydrated potatoes of acceptable color; however, it required more time.     

Word reordering on multiple pivots for the Japanese and Indonesian language pair

Machine Translation - We investigated multiple pivot approaches for the Japanese and Indonesian (Ja–Id) language pair in phrase-based statistical machine translation (SMT). We used four...     

Peer-assisted adaptation in periodic broadcasting of videos for heterogeneous clients

The increasing use of streaming applications and wide variety of devices, such as handheld personal organizers, have raised new challenges, such as the provision of access to multimedia content for devices with limited computing and bandwidth capabilities. In this paper, we propose a technique for periodic broadcasting. Our technique allows clients with low bandwidth capability to be served in the same period as high-bandwidth clients, using peer-to-peer streaming between clients, and also works for clients with downstream capability below the video bit rate. In the proposed system, the server builds multicast trees of clients that allow clients with low bandwidth to be served by other clients with sufficient upstream bandwidth. Clients below the video bit rate will suffer additional, but only moderately noticeable, delays that occur as video is converted to lower quality. We performed extensive simulation and showed that our system can provide improved service performance for heterogeneous clients on periodic broadcasting protocols.     

Critical roasting level determines bioactive content and antioxidant activity of Robusta coffee beans

Food Science and Biotechnology - Indonesian Lampung Robusta coffee green beans were roasted at eight roasting levels (green bean, early yellow, brown, 1st crack done, very light, light, medium, and...     

Suppression of Proliferation of Human Glioblastoma Cells by Combined Phosphodiesterase and Multidrug Resistance-Associated Protein 1 Inhibition

The paucity of currently available therapies for glioblastoma multiforme requires novel approaches to the treatment of this brain tumour. Disrupting cyclic nucleotide-signalling through phosphodiesterase (PDE) inhibition may be a promising way of suppressing glioblastoma growth. Here, we examined the effects of 28 PDE inhibitors, covering all the major PDE classes, on the proliferation of the human U87MG, A172 and T98G glioblastoma cells. The PDE10A inhibitors PF-2545920, PQ10 and papaverine, the PDE3/4 inhibitor trequinsin and the putative PDE5 inhibitor MY-5445 potently decreased glioblastoma cell proliferation. The synergistic suppression of glioblastoma cell proliferation was achieved by combining PF-2545920 and MY-5445. Furthermore, a co-incubation with drugs that block the activity of the multidrug resistance-associated protein 1 (MRP1) augmented these effects. In particular, a combination comprising the MRP1 inhibitor reversan, PF-2545920 and MY-5445, all at low micromolar concentrations, afforded nearly complete inhibition of glioblastoma cell growth. Thus, the potent suppression of glioblastoma cell viability may be achieved by combining MRP1 inhibitors with PDE inhibitors at a lower toxicity than that of the standard chemotherapeutic agents, thereby providing a new combination therapy for this challenging malignancy.     

Constructing a Thin Disordered Self-Protective Layer on the LiNiO2 Primary Particles Against Oxygen Release

One of the major challenges facing the application of layered LiNiO₂ (LNO) cathode materials is the oxygen release upon electrochemical cycling. Here it is shown that tailoring the provided lithium content during synthesis process can create a disordered layered Li_1-xNi_1+xO₂ phase at the primary particle surface. The disordered surface, which serves as a self-protective layer to alleviate the oxygen loss, possesses the same layered rhombohedral structure (R$\overline{3}$m) as the inner core of primary particles of the Li_1-xNi_1+xO₂ (x ≈ 0). With advanced synchrotron-based x-ray 3D imaging and spectroscopic techniques, a macroporous architecture within the agglomerates of LNO with ordered surface (LNO-OS) is revealed after only 40 cycles, concomitant with the reduction of nickel on the primary particle surface throughout the whole secondary particles. Such chemomechanical degradation accelerates the deterioration of LNO-OS cathodes. Comparably, there are only slight changes in the nickel valence state and interior architecture of LNO with a thin disordered surface layer (LNO-DS) after cycling, mainly arising from an improved robustness of the oxygen framework on the surface. More importantly, the disordered surface can suppress the detrimental H2 ⇋ H3 phase transition upon cycling compared to the ordered one.